An improved Kahn transmitter architecture based on delta-sigma modulation

A new architecture for linear high efficiency power amplifiers and transmitters is proposed. The essential idea is to apply delta-sigma modulation to the signal envelopes in the Kahn transmitters. While in traditional Kahn techniques the original signal envelope is restored before the final-stage power amplifier is modulated, in the proposed scheme, the power amplifier undergoes digital modulations and the signal envelope is restored from passing through a high Q bandpass filter at the output. Simulations based on power GaAs FET models show 31% improvements on power efficiency and 5 dB improvement in IM3 compared to traditional Kahn techniques.